One important consideration that is associated with producing electronic assemblies that include stacked electronic devices (e.g., dies or chips) relates to effectively dissipating heat from the bottom electronic device in a stack of electronic devices. Another important consideration relates to the ability to handle thin wafers or dice that include through silicon vias (TSVs) for subsequent stacking of one or more additional electronic devices onto the thin wafers or dice.
FIG. 1 shows a prior art electronic package 10 that uses a high thermal conductivity mold material to dissipate heat from the bottom electronic device in a stack of electronic devices. The high thermal conductivity mold material is positioned between a top most electronic device in the stack of electronic devices and a heat spreader.
FIG. 2 shows another prior art electronic package 20 that uses a stepped integrated heat spreader (IHS) to dissipate heat from the bottom electronic device in a stack of electronic devices. Using a stepped IHS often offers limited control of the thickness of the thermal interface material (TIM) bonding layer that is between a top most electronic device in the stack of electronic devices and the IHS. The thickness of the TIM bonding layer is difficult to control due to tolerance issues that are typically associated with stacking electronic devices.
One of the ways that thermal management issues are addressed in the prior art electronic assemblies illustrated in FIGS. 1 and 2 is to increase the thermal conductivity of the TIM bonding layer. However, increasing the thermal conductivity of the TIM bonding layer is usually not adequate alone.
The thickness of the bottom electronic device in the stack of electronic devices that are included in the prior art electronic assemblies illustrated in FIGS. 1 and 2 is typically about 100 um. This minimal thickness of the bottom electronic device often makes it problematic to safely and efficiently handle the bottom electronic device during production of the electronic assemblies that include stacked electronic devices.